Cleanups: Add comments to ease code understanding
Typo
Docs: Expand non-conformance notes for PHP format
Docs: Replace formats supported section with link to PHP format docs
Fix: Reset prename when exiting the array

Perhaps several (not nested) arrays are declared in the same file, or
perhaps the file has mixed dialects for setting the localization strings.
Cleanups
Docs: Add more non-conformance cases for PHP format
Remove dead code in po2tmx.py
Docs: Fix example on styleguide
Cleanups: Remove unnecessary example on styleguide
Cleanups: Use code-block for styleguide examples